A while back, I had a tech who was having some trouble finding a 35 PSI (2.41 bar) make-on-fall pressure switch. One adjustable switch in the catalog said (SPDT), but he didn't quite understand what that meant. In that case, it means single-pole, double-throw, and the “double-throw” part means that the switch has terminals in both the […]

If you don't do a lot of commercial work, you may see a system like the one above and wonder what the heck it is. It is a 100% fresh air unit or a makeup air unit. You will see them more and more as codes start to reflect that balanced ventilation and conditioned outdoor […]

In our line of work, it's all too easy to let your bad experiences inform your present and future experiences. That is especially true if you have a high emotional range. Having “emotional range” is a polite way of saying that you're a bit up and down (maybe even neurotic). We don’t believe that sensitivity […]